Math-o-logical (2024)

As mentioned in the previous post, TNP does not use any static modifiers. This is one of the rules which bound the system (another being that all character statistics must be derived from class dice.) Part of the reason for this is to simplify some of the math, but also to encourage "teamwork bonuses" for increasing your chance to hit, in combat.

That all being said, I feel like the flat 55% success rate just doesn't cut it; I've even heard that some D&D-alike systems have chosen to eschew attack rolls altogether. As such, one of the things I've been juggling with my future project, is having a simple attack bonus to increase the hit chance -- namely, the weapon dice mechanics, as well as the d6 pool mechanics which I've touched on in recent posts. So it's probably a good time to look at the math a little bit.

Sticking with a DC10:

• 1d20+1d4 gives us a 50% hit chance, and 17.5% crit chance
• 1d20+1d6 gives us a 50% hit chance, and 22.5% crit chance
• adding the higher of 1d4 and 1d6 to a d20 gives us a 50% hit chance, and 24.58% crit chance
• adding the highest 1d6 out of 5d6 to a d20 gives us a 50% hit chance, and 32.15% crit chance

So what does that mean, in practical terms? Well, one thing I've always talked about within the designs of TNP is that the math should have a "meaningful" chance of failure -- a number I've typically pegged between about 15%-20%, particularly for skills. If we're incorporating these sorts of bonuses into the designs of the combat math, we can see that we're rapidly approaching that threshold for failure chance; we can't really increase hit chance much higher, particularly if "teamwork bonuses" are meant to be over and above what's accounted for here.

The knock-on effect is that it brings into question the idea of using 1d10 for skill checks. Apart from the ergonomic value of using percentile d10s for an advantage mechanic, if the combat system is using d20, and is based around the assumption of a hit rate in the range of 67.5%-82.15%... then why not just go back to using d20 for skills, too? With the idea being to unify all of the dice bonuses into d6 pool mechanics, this would have the added benefit of allowing attributes to be +0 or even possibly go into negatives, while still allowing the skill math to work properly. The only big sticking point (for me) is deciding what (if anything) a critical success on a skill check should do; using a d10 vs. DC10 system neatly side-steps this consideration.

The other question is whether this scale makes more sense than the d10 skill check math:

• 1d20-1d6 = 37.5%
• 1d20+0 = 55%
• 1d20+1d6 = 72.5%
  
• 1d20+[highest 1 of 2d6] = 77.36%
• 1d20+[highest 1 of 5d6] = 82.15%

Another thing I'm considering is that while most special abilities will be keyed off of attributes (for example, a +2 DEX providing a pool of 2d6) the flat modifier for those attributes might also be used as a damage bonus, just to improve the "oomph" of basic attacks. Another use for flat modifiers might be a sort of 'mastery' mechanic, whereby a die result cannot be lower than the modifier, or could be rerolled if lower/equal to the modifier.

If we're sticking with the 5 attributes of TNP (Strength, Dexterity, Intelligence, Charisma, Agility) and we're assuming the d6 pool will consist of one attribute, plus any "teamwork bonuses," then it stands to reason that our attributes shouldn't really exceed 3 (working from the TNP cap of 5d6 "extra damage" as our baseline.) So how many "points" should we be able to spread, between our attributes? Assuming a minimum attribute of +1 and maximum of +3, we could use 10 points to give us an array of +3/+3/+2/+1/+1. I almost wonder if the better alternative is to start with +1 to all, and then have class/background/whatever give you a +2 to two stats (as in 4e) or +2 to one and +1 to another (as in 5e). I think it'll really come down to what "feels" like the "right" amount of points.

...

That wraps up another meandering post, for now.
Check back on August 21st for the next one.